You can generally only get the covers.
http://stores.ebay.com/CM-Tactical_W...10207533QQtZkm
Real stuff, decently priced. Go by the size of your BDU shirt, and not T-shirt sizes (they're one size smaller than t-shirt sizes, generally speaking).
The IOTV is barely even being fielded by the guys who need it, so you won't really find them. I've also yet to see replicas that are worth buying.
The IBA is fairly easy to find replicas for but the colours are what suck mostly.
Theses are decent replicas, I've seen em before, not the best, but you don't really need the best for airsoft
http://cgi.ebay.com/ACU-Marine-Inter...742.m153.l1262